Mechanism behind columnar pattern formation during directional quenching-induced phase separation

Abstract

It is known that there is a universality behind pattern formation during phase separation induced by homogeneous quenching. However, this universality is broken when quenching is carried out in an inhomogeneous manner. An example is directional quenching, where a columnar or lamellar pattern may be formed depending on the speed of the quenching front. Despite the wide industrial and technological interest in pattern formation, the mechanism behind the formation of these columnar patterns is not yet understood. Here we investigated the dynamics of pattern formation induced by directional quenching using numerical simulations. We found that the interface of the first layer that is formed fluctuates, and a columnar pattern is formed when this fluctuation grows. In addition, we reveal that the effective confinement effect induced by the quenching front plays an important role in determining the nature of the fluctuations at the interface.